1. Field of the Invention
The present invention relates to a tube-type container that comprises synthetic resin having elasticity restoring strength and that stores a fluid inside it.
2. Description of the Related Art
Regarding this kind of tube-shaped containers, replacing conventional tubes comprising a metal or aluminum foil laminated material, tubes having composition of solely synthetic resin or a synthetic resin and aluminum laminated material (In this specification, these are generically named xe2x80x9cmade of synthetic resinsxe2x80x9d.) have been used in recent years.
Because such synthetic resin tube has elasticity-restoring strength, if applying a pressure to the tube and then releasing the pressure applied after discharging a fluid stored inside it, there is a problem that the elasticity-restoring strength of the tube causes the air to flow backward to the fluid-storing portion from the opening portion for discharging the fluid. As a result, the quality of the fluid stored deteriorates.
For this reason, a tube-type container, which has a flat-plate-shaped valve body attached in the opening portion for discharging a fluid so that the opening portion is blocked off by this valve body when the elasticity of the tube is restored, was proposed (e.g., Japanese Patent Laid-open No.1995-112749, Japanese Patent Laid-open No.1998-157751, Utility Model Patent Laid-open No.1984-26748, etc.).
In the tube-type container with such a conventional flat-plate-shaped valve body attached, if the tube carries out elasticity-restoring strength movements slowly, the valve body does not block off the opening portion of the tube-type container and there are some cases where the air flows backward to the fluid-storing portion.
Additionally, in a tube-type container with the conventional flat-plate-shaped valve body attached, there are problems that the cost of production is high because high process precision is required, and that durability is low.
The present invention was achieved to solve the above-mentioned problems. The present invention aims to provide a tube-type container by which back-flow of air can be reliably prevented although the construction is simple, and which is excellent in durability.
In an embodiment, the present invention is characterized in that a tube-shaped container comprises: a tube-type container main body that comprises synthetic resin having elasticity-restoring strength and that possesses a fluid-storing portion for storing a fluid inside it and an opening portion for discharging the fluid, which is formed in one end of the fluid-storing portion; a tube-shaped material possessing a fluid flow path, which has a nearly tube-like shape that can be attached inside the opening portion of the container main body and on the inner circumference of which the first tapered portion with its internal diameter gradually reducing toward the side of the fluid-storing portion is formed; the second tapered portion that can block off the fluid flow path in the tube-shaped material by contacting the first tapered portion in the tube-shaped material; and a valve body that possesses a regulating portion regulating a distance by contacting the tube-shaped material so that the second tapered portion does not move away beyond the designated distance.
The present invention is not limited to the above specific embodiment but effectively provides a backflow preventive tube-type container comprising: (a) a tube-type container main body for storing a fluid therein, said main body having a mouth portion for discharging the fluid, said main body being elastic when the fluid is stored therein; (b) a cylinder-shaped material fitted in the mouth portion, said cylinder-shaped material having at a bottom an opening through which the fluid passes; (c) a valve body comprising a convex portion configured to be liquid-tightly fitted in the opening, said valve body being movable in said cylinder-shaped material only in an axial direction thereof, wherein said valve body; and (d) a support for limiting movement of the valve body away from the opening, wherein when the main body is pressed by external force, the fluid pushes the valve body and is discharged through the opening, and when the external force is released, the pressure inside the main body becomes lower than the pressure outside the main body due to elasticity of the main body, thereby retracting the fluid at the opening and closing the valve body. Various embodiments included in the present invention will be explained later.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular embodiment of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.